ejecta blanket

The 4-km-diameter crater Linne in the western part
of Mare Serenitatis on the Moon. This Apollo 15 photo shows the bright
ejecta blanket surrounding this relatively very young crater. Image
credit: NASA

A generally symmetrical apron of ejecta that surrounds
an impact crater. It is layered thickly
at the crater's rim and thin to discontinuous at the blanket's outer edge.

The extent of an ejecta blanket is determined by a number of factors including
the size and mass of the impacting body (meteorite, asteroid, or comet),
the surface gravity, and the atmospheric
pressure. Where there is no atmosphere and the surface gravity is low, the
ejecta blanket may extend to several times the radius of the central crater.
On the other hand, on a world where both the atmospheric pressure and surface
gravity are relatively high, the ejecta blanket will not reach far beyond
the crater rim.